Multiple switch-board



(No Model.)

M. G. KELLOGG.

MULTIPLE SWITCH BOARD.

No. 887,888. Patented Aug. 14, 1888.

N. PETERS, Pnuxwunogmmr. walmngm. n. c.

lhyrrnn STaTns Parenti @Tries MIL() G. KELLOGG, OF HYDE PARK, ILLINOIS.

MULTlPLE SWlTCH=BOARD.

SPECIFICATION forming part of Letters Patent No. 387,888, dated August 14, 1888.

Application filed May Q1, 1587. Serial No. 238,948. (No model.)

To @ZZ whom t may concern/.-

Be it known that I, Mino G. KELLoee, of Hyde Park, Illinois, have invented certain new and useful Improvements in Multiple Switch-Boards for Telephone-Exchanges, of which the following is a full, clear, concise, and exact description, reference being had to the accompanying drawings, forming a part of this specification.

My invention consists, first, in a multiple switch-board system of operating an exchange and testing at one board to determine whether any given line is in use at any other board, which system I shall hereinafter describe and claim in detail.

It consists, secondly, of a certain construetion of springjacl; switch,which I shall hereinafter describe and claim in detail, said switch being adapted to said multiple switch-board system mentioned above and to other systems of telephoneexchange switch-boards.

In my multiple switchboard system I place as many swtch-boards in the central office as are found necessary or desirable in order to properly answer the calls and disconnect and connect the subscribers lines. On each board I place for each line which centers at the ofce aspring-jack orsimilar switch having four insulated contact-pieces, two of which are normally in contact, said switch being adapted to receive a plug, and when the plug is inserted to disconnect the pieces which are normally in contact and connect one of them with the ilexible conductor attached to the plug, and at the same time to bringthe two other contact-pieces in electrical connection, and when the plug is withdrawn to disconnect these latter pieces and connect again the first two. The pieces mentioned above which are normally in contact are mainline contact-points, and the other two are local contactpoints. The spring-jack switches or" a line on the different boards may be called a series or' spring-jack switches.77

Figures 1f" and l are front views of sections of two or more multiple switch-boards to which the saine lines are connected. Fig. 2 shows a complete diagram of the boards with all the centralbflice apparatus, circuits, and connections necessary to operate them according to my invention.

In the drawings like parts and apparatus are indicated by the same letters of reference.

In Fig. 2, A is asectional view of theswitehboard shown in Fig. l, as indicated by line d e, and A is a sectional view of the switchboard shown in Fig. l, as indicated by line cZ c.

ci Z represent rubber strips ou which the metal parts of the spring-jack switches are mounted. These strips may be long enough to receive any convenient number ol' springjack parts.

Z Z are rectilinear holes through the fronts of and at one of the edges of the strips, adapted to receive the switch plugs. The Contact springs are mounted to the rear ol' and are parallel to the holes Z Z to which they belong, as shown. The contact-points 7i h, on which the contact-springs or spring-levers normally bear, pass through the rubber strip, as shown, and each has a connecting-piece, li', as shown. Toward the front of the switch holes, and along their lower faces, as shown, I place two contact-pieces normally insulated from each other and from the rest of the apparatus, ex-

-cept by conducting-wires, as will hereinafter be described. These contactpieces are marked t and j, They extend to the front of the holes, so that the contact'points of a double test-plug may be brought in contact with them.

The switch-plugs are substantially as shown, and as will hereinafter be described. The several parts mentioned above areso made, shaped, arranged, and adj usted that when a switchplug is inserted into a switch-hole, as shown, it raises the spring-lever in the rear of the hole from the contactpoint li, on which it normally bears, and the flexible cord is connected to the spring-lever, while the contactpieces i an dj are electrically connected through the medium of the metal piece m of the switchplug, which then touches both i andj of the switch.

Each section of a rubber strip,with its springlever, contact-point, eontalctpieces, and the hole, all arranged and operating as above, may be called a spring-jack switch. 7 The rubber strips are placed one above the other, as shown. The lower edge of one strip therefore provides the upper edges of the holes of the strip which is below it. The holes may be of any convenient shape adapted to the shapes and arrangement of the parts used.

Two subscribers lines are shown. l They are ICO s @emacs marked line No.1 and line No.2. sand s erators telephone, and B is her calling geare the spring-jack switches of line No. 1 on erator or battery. The letter G in each case the two boards, and r and r are the springrepresents aground connection. The circuits 7o jack switches of line No. 2 on the two boards. arc substantially as shown.

5 rlhe circuits and connections of the lines and T T are operators testing systems at the switches are as follows: Line No. 1, for intwo boards, one at each board. C is the rub-, stance, after entering the office, passes first to ber handle of the test-plug. spring-lever g of switch s, and thence through p q are the contact-pieces of the test-plug, 75 contact-point lz and connecting-piece It of that so made, placed, and adjusted that the oper- Io switch and wire s to spring-lever g of switch ator can readily connect them simultaneously el s, and thence through contactpoint h and conto any pair of contact-pieces and j of any4 .ix

necting-piece h of that switch and wire 8 to switch at her board-ns, for instance, p to t' its annunciator, and thence to the ground. and q toj, or the reverse. 8o The contact-pieces e' t' of the switches s and s E is an electric bell or other test-receiving are connected together by wire 3, and the instrument, and B is an electric battery, both contact-pieces j j of the switches s and s are being placed in the loop which connects the connected together by wire sm. In asimilar two contact-pieces p q, as shown. The oonmanner all of the other lines could be connection between the apparatus E and B and 85 neet-ed to their switches and the contact-pieces the test-plug is by flexible conductors of suffiof the switches be connected together. Other cient length, so that the operator may readily boards might be added to the exchange, and apply the contact-piecesp q of her test-plug the connections of the lines and the switches to the pair of contact piecesi and j of any on them would be similar' to the above and line at her board, as described. 9o i such as will be evident to those skilled in the Each operator has one testing system and` art. one cord system. The cords should be of sufif s s', Fig. 2, are operators systems of cords, cientlength andtheapparatusshould beplaced with plugs, keys, switches, clearing-out anin convenient arrangement at her board, so nu/nciators, operators telephone, calling genthat she can conveniently operate the eX- 95 erator or battery, and circuits. One system change system. The levers of all switches Y 3o is shown at each board, and is intended for should normally rest on z z; but the levers of one operator. Only one pair of cords, with a switch are to be moved to 1/ y when the opits plugs, key, switch, and clearing-out anerator desires to use her telephone with a pair nunciator, is shown in each system. Others of cords to which the switch belongs. roc could be added in a manner which will be The method of operating the exchange sysapparent to those'skilled in the art. tem at either board,includinganswering calls,

D D are the two switch-plugs connected to making connections, sending signals, clearingthe pair of cords and adapted to be inserted out connections, Src., are such as will be apin the line-switches. parent on an examination of the apparatus 105 m m are the metal pieces of the plugs, adapted. and circuits shown. 4o to come in contact with the spring-levers g of For convenience, I call a pair of contactthe switches and connect them with the cords pieces t' and j of a switch a pair of testof the plugs. m m are metal pieces of the bolts.7 The pairs of test-bolts of the switches plugs, adapted to come in contact with pieces of a line on the different boards may be called 11o v2 and j of a switch, when the plug is inserted a series of pairs of test-bolts.77 into a switch, and connect them together. It will be seen that when there is no plug in n n are the rubber insulations oli' the plugs. any switch of a line none of the test-bolts I of The pieces m m extend to the bottom of the the lineare in electric connection with the corplugs, as shown, and are adapted to rest on responding test-boltj, and if atest-plug is ap- 1x5 the metal strip o, which is connected to the plied, as above, to any pair of test-bolts of a ,50 ground and normally connects the cords with line in such a condition there is not a comtheground. VVeightsas is usual,or other simiplete circuit established through the bell and lar devices, may be used to bring the metal battery of the plug,and the bell will not ring. piece m of a plug in normal contact with the If, on the other hand, there is a switch-plug in 12o strip o and form a good connection. The plugs any switch of a line,an electric connection ex- 1 5 5 should be inserted into the switches in such ists between any test-bolt i of the line and its a manner as to make the connections above corresponding test-bolt j, and if a test-plug is described. A plug is shown thus inserted in then applied toany pair of test-bolts of the one switch. line the bell will ring. `Consequently an oper- 125 Y is a looping-in switch. y y and z z are the ator may at any time find out whether a given 6o connecting-bolts of the switcl1,on which the opline is in use at some other board by applying erator may at will place the pair of switchher test-plug,as above,to the pair of test-bolts levers. The cross piece between the levers of the line,and if her bell rings she knows that may be of rubber, as is usual, or of other snitone of the switches of the line has a plug in; 13o

able insulating material. but if it does not ring she knows that none of 7c is a calling key, constructed, connected, the switches of the line have plugs in them. f.'\ and operating as shown. I claim as my invention and desire to secure ,i1

o is a clearing-out annunciator. t is an opby Letters Patent-n 1. A spring-jack switch containing a contact point or piece, a spring -lever normally bearing on said contact-point, and two insulated contact-pieces, all mounted on an insulatingstrip, said lever being transverse to the front of said strip, said strip having through its front a transverse rectilinear hole in front of said lever, said insulated contact-pieces being mounted on one of the faces of said hole and adapted to be crossed with each other by the insertion of the switclrplug, substantially as set forth.

2. A springjack switch containing a contact point or piece,a spring-lever normally bearing on said contact-point, and two insulated contactpieces, all mounted on an insulating-strip, said lever being transverse to the front of said strip, said strip having through its front a. transverse rectilinear hole in front of said lever, said insulated contact-pieces being mounted on one of the faces of said hole and extending to or near the front of said hole, substantially as and for the purpose set forth.

3. In a multiple switch-board, the combination of a series of lineswitehes,aseries of testbolts, one pair for each switch, insulated from each other and from the switch, continuous circuit-connections between the similar testbolts of the different boards, circuit-connections between the switches, plugging devices for connecting the subscribers lines at the switches and for simultaneously crossing the test-bolts at the plugged switch, the test-plug having double contacts adapted to close the test-circuitthrough the pair of testbolts at the tested switch and through both contacts of the test-plug, and a loop-circuit, including a bat tery and signal, connected with both contacts of the test-plug and adapted to be closed through the contacts of the plug, whereby a test-circuit is established through the testbolts at both the plugged switch and the tested switch and through both contacts of the testplug and the signal-circuit connected therewith, substantially as set forth.

4. In a multiple switch-board, the combination of the main lines, a series of switches at cach board for each line, a pair of normally closed contactpieces at each switch for each line, a pair of testbolts, t and j, at each switch, continuous connectingwires 8" for the bolts i, and continuous connecting- Wires sm for the bolts j, a switch plug having two parallel insulated contact pieces adapted to open the mainline contacts at the plugged switch and connect one of them-With one contact-piece of the plug and to cross the test-bolts at the plugged switch, and a testplug having double contacts adapted to close the test-circuit through the pair of test-bolts at the tested switch, and a 1oopcircuitconnccted with the contacts, including a battery and signal, substantially as set forth.

MILO G. KELLOGG.

'Witn esses:

MILTON HEAD, WALLACE L. DEWOLF. 

